Caption: Neural network. Artwork of a multipolar nerve cell (neurone) against an electronic integrated circuit (chip). The tentacle-like cell processes appear interwoven into the chip. Neural network technology aspires to the complexity & power of an animal's nervous system, relying upon the same principles of stimulus- response. Animal nerve cells, receptors & fibres are replaced by input devices, microprocessor chips and very rapid computer analysis and output. The development of neural networks faces many obstacles, not least the current lack of understanding of the intimate workings of the animal brain & nervous system.